A plasma display panel (PDP) is a flat display device using a plasma phenomenon, which is also called a gas-discharge phenomenon since a discharge is generated in the panel when a potential greater than a certain level is applied to two electrodes separated from each other under a gas atmosphere in a non-vacuum state. Such gas-discharge phenomenon is applied to display an image in the plasma display panel.
FIG. 1 is a perspective view of plasma display panel 1. As shown in FIG. 1, a plurality of barrier ribs 7 are disposed between front substrate 3 and back substrate 5 with a certain distance therebetween to form a discharge cell. In the cell space, red, green, and blue phosphors 9 are formed. On back substrate 5, address electrodes 11 to be applied with the address signal are formed. On front substrate 3, a pair of sustain electrodes (electrode X 13, electrode Y 15) is formed in one discharge cell in a perpendicular direction to that of the address electrodes. To the discharge space, a discharge gas such as Ne—Xe or He—Xe is injected. That is, three electrodes are mounted in the discharge space of the plasma display panel, which is coated with the red, the green, and the blue phosphors in a regular pattern. When a certain level of voltage is applied between these electrodes, plasma discharge occurs to generate ultraviolet rays, and thereby the phosphors are excited to emit the light.
Phosphor layer 9 is prepared by coating a phosphor paste on the surface of a discharge cell surrounded by front substrate 3, back substrate 5, and barrier rib 7. The phosphor paste is prepared by adding the phosphor to a binder and a solvent. When the side thickness of the phosphor contacting the barrier rib is too thick, a panel spot may occur in a slanting direction so that the luminance is decreased. However, attempts to control the side thickness of the phosphor layer in order to improve the optical characteristics of the plasma display panel have not yet been made.